Lisdexamfetamine dimesylate in ADHD phase 3 data presented

SAN DIEGO – October 30, 2006 – Shire plc (LSE: SHP, NASDAQ: SHPGY, TSX: SHQ) and its collaborative partner New River Pharmaceuticals Inc. (NASDAQ: NRPH) announced today that their investigational ADHD treatment, lisdexamfetamine dimesylate (also known as NRP104 or LDX), yielded a 60 percent improvement in the primary rating scale scores for symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD) in children aged 6 to 12 years who received six months of treatment in an open-label phase III study. Results also demonstrated that at 6 months, 95 percent of children taking lisdexamfetamine dimesylate (NRP104/LDX) produced a "much improved" or "very much improved" rating on the Clinical Global Impressions – Improvement score. These results were presented last weekend at a national meeting of child and adolescent psychiatrists.

Final results of this study, which will assess lisdexamfetamine dimesylate (NRP104/LDX) treatment in children with ADHD for one year, are expected in mid-2007.

"This study further demonstrates the potential of lisdexamfetamine dimesylate to be an effective treatment option for children with ADHD," said Ann Childress, M.D., study investigator and president at the Center for Psychiatry and Behavioral Medicine, Inc. in Las Vegas, Nev. "Lisdexamfetamine dimesylate was designed to offer the effectiveness of a stimulant with a novel prodrug formulation that is inactive until metabolized in the body."

New River Pharmaceuticals designed lisdexamfetamine dimesylate as a new ADHD medication in which d-amphetamine is covalently linked to l-lysine, a naturally occurring amino acid. Designed to provide efficacy throughout the day through 6 p.m., lisdexamfetamine dimesylate (NRP104/LDX) remains inactive until converted in the body and the active drug is released. In January 2005, New River signed a collaborative agreement with Shire to develop and commercialize lisdexamfetamine dimesylate (NRP104/LDX). New River received an approvable letter from the U.S. Food and Drug Administration (FDA) for lisdexamfetamine dimesylate (NRP104/LDX) on October 6, 2006. According to the FDA's letter, marketing approval is contingent upon final scheduling by the U.S. Drug Enforcement Administration (DEA). The FDA has not requested any additional studies. Shire and New River are preparing for a product launch in Q2 2007, pending final labeling and scheduling discussions.

Interim Results of Open Label Phase III Study

The subjects in this study had previously participated in either of two blinded clinical trials of lisdexamfetamine dimesylate (NRP104/LDX). All patients in the current trial received lisdexamfetamine dimesylate (NRP104/LDX) 30 mg in the first week. Investigators titrated patients' daily dosage by 20 mg at weekly intervals during subsequent visits to achieve optimal efficacy and tolerability. The maximum daily dose was 70 mg.

In this study of 269 children with ADHD, six months of treatment with lisdexamfetamine dimesylate (NRP104/LDX) resulted in significant reductions in the participants' average total scores on the Attention-Deficit/Hyperactivity Disorder Rating Scale (ADHD-RS-IV). Specifically, the children had an average reduction of 26.9 points which represents an average improvement of more than 60 percent. ADHD-RS-IV, the primary efficacy measurement tool for the study, is a standard test for assessing symptoms of ADHD. The scale, which contains 18 items, is based on the ADHD diagnostic criteria as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision®, a publication of the American Psychiatric Association.

Investigators also measured the efficacy of lisdexamfetamine dimesylate (NRP104/LDX) with the Clinical Global Impressions - Improvement (CGI-I) scale, in which 95 percent of patients' symptoms were rated as "much improved" or "very much improved" after six months of treatment. The CGI is a standard assessment tool used to rate the severity of illness, change of improvement over time and efficacy of medication.

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In this study, lisdexamfetamine dimesylate (NRP104/LDX) was generally well-tolerated. The medication's side effects were similar to that of currently marketed ADHD stimulant medications. The most frequently reported adverse events for lisdexamfetamine dimesylate (NRP104/LDX) were decreased appetite, insomnia, headache and decreased weight.

New River Pharmaceuticals Inc. is supporting this study.

About ADHD

Approximately 7.8 percent of all school-age children, or about 4.4 million U.S. children aged 4 to 17 years, have been diagnosed with ADHD at some point in their lives, according to the U.S. Centers for Disease Control and Prevention (CDC). ADHD is one of the most common psychiatric disorders in children and adolescents. ADHD is a neurobiological psychiatric disorder that manifests as a persistent pattern of inattention and/or hyperactivity-impulsivity more frequent and severe than typically observed in individuals at a comparable level of development. To be properly diagnosed with ADHD, a child needs to demonstrate at least six of nine symptoms of inattention; at least six of nine symptoms of hyperactivity/impulsivity; the onset of such symptoms before age 7 years; that some impairment from the symptoms is present in two or more settings (e.g., at school and home); that the symptoms have been present for at least six months and that there is clinically significant impairment in social, academic or occupational functioning.

Although there is no "cure" for ADHD, there are accepted treatments that specifically target its symptoms. The most common standard treatments include educational approaches, psychological or behavioral modification, and medication.

Shire's strategic goal is to become the leading specialty pharmaceutical company that focuses on meeting the needs of the specialist physician. Shire focuses its business on attention deficit and hyperactivity disorder (ADHD), human genetic therapies (HGT), gastrointestinal (GI) and renal diseases. The structure is sufficiently flexible to allow Shire to target new therapeutic areas to the extent opportunities arise through acquisitions. Shire believes that a carefully selected portfolio of products with a strategically aligned and relatively small-scale sales force will deliver strong results.

Shire's focused strategy is to develop and market products for specialty physicians. Shire's in-licensing, merger and acquisition efforts are focused on products in niche markets with strong intellectual property protection either in the US or Europe.

For further information on Shire, please visit the Company's website: www.shire.com.

Statements included herein that are not historical facts are forward-looking statements. Such forward-looking statements involve a number of risks and uncertainties and are subject to change at any time. In the event such risks or uncertainties materialize, Shire's results could be materially affected. The risks and uncertainties include, but are not limited to, risks associated with: the inherent uncertainty of pharmaceutical research, product development, manufacturing and commercialization; the impact of competitive products, including, but not limited to the impact of those on Shire's Attention Deficit and Hyperactivity Disorder (ADHD) franchise; patents, including but not limited to, legal challenges relating to Shire's ADHD franchise; government regulation and approval, including but not limited to the expected product approval dates of SPD503 (guanfacine extended release) (ADHD), SPD465 (extended release of mixed amphetamine salts) (ADHD), MESAVANCE (mesalamine) with MMX technology (SPD 476) (ulcerative colitis), ELAPRASE (idursulfase) (Hunter Syndrome) and NRP104 (lisdexamfetamine dimesylate) (ADHD), including its scheduling classification by the Drug Enforcement Administration in the United States; Shire's ability to secure new products for commercialization and/or development; and other risks and uncertainties detailed from time to time in Shire's and its predecessor registrant Shire Pharmaceuticals Group plc's filings with the Securities and Exchange Commission, particularly Shire plc's Annual Report on Form 10-K for the year ended December 31, 2005.

New River Pharmaceuticals Inc. is a specialty pharmaceutical company developing novel pharmaceuticals that are generational improvements of widely prescribed drugs in large and growing markets.
For further information on New River, please visit the company's website at www.nrpharma.com.

This press release contains certain forward-looking information that is intended to be covered by the safe harbor for "forward-looking statements" provided by the Private Securities Litigation Reform Act of 1995. Forward- looking statements are statements that are not historical facts. Words such as "expect(s)," "feel(s)," "believe(s)," "will," "may," "anticipate(s)" and similar expressions are intended to identify forward-looking statements. These statements include, but are not limited to, financial projections and estimates and their underlying assumptions; statements regarding plans, objectives and expectations with respect to future operations, products and services; and statements regarding future performance. Such statements are subject to certain risks and uncertainties, many of which are difficult to predict and generally beyond the control of New River Pharmaceuticals, that could cause actual results to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks and uncertainties include: those discussed and identified in the New River Pharmaceuticals Inc. annual report on Form 10-K, filed with the SEC on March 15, 2006; the timing, progress and likelihood of success of our product research and development programs; the timing and status of our preclinical and clinical development of potential drugs; the likelihood of success of our drug products in clinical trials and the regulatory approval process; our drug products' efficacy, abuse and tamper resistance, resistance to intravenous abuse, onset and duration of drug action, ability to provide protection from overdose, ability to improve patients' symptoms, incidence of adverse events, ability to reduce opioid tolerance, ability to reduce therapeutic variability, and ability to reduce the risks associated with certain therapies; the ability to develop, manufacture, launch and market our drug products; our projections for future revenues, profitability and ability to achieve certain threshold sales targets; our estimates regarding our capital requirements and our needs for additional financing; the likelihood of obtaining favorable scheduling and labeling of our drug products; the likelihood of regulatory approval under the Federal Food, Drug, and Cosmetic Act without having to conduct long and costly trials to generate all of the data which are often required in connection with a traditional new chemical entity; our ability to develop safer and improved versions of widely prescribed drugs using our Carrierwave (TM) technology; our success in developing our own sales and marketing capabilities for our lead product candidate, NRP104; and our ability to obtain favorable patent claims. Readers are cautioned not to place undue reliance on these forward-looking statements that speak only as of the date hereof. New River Pharmaceuticals does not undertake any obligation to republish revised forward-looking statements to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events. Readers are also urged to carefully review and consider the various disclosures in New River Pharmaceuticals' annual report on Form 10-K, filed with the SEC on March 15, 2006, as well as other public filings with the SEC.